Yeah, warlocks are rather boring after a while, from my experience, I'd also recommend to play a regular caster, whether or not your DM allows warlock. You can make an effective and fun warlock with versatility, but it requires you to make heavy usage of the only class features your DM didn't seem to mind (and IMO the most powerful ones, far more than that piddly eldritch blast): the ability to take 10 on UMD and later on craft any item you have the feat for. After just a few levels, with tons of wands and scrolls, you can have a lot of combat options and utility spells. If you do go warlock, you'll want to think of a lot of useful low level spells to get in item form and max that UMD score.
A warlock is feat starved for this precise reason.
He needs the item creation feats in order to make use of one of his class abilities and he does not gain any bonus feats to accomodate that.
He benefits from the Fey/Fiendish heritage feat chains tremendously, likewise the precise shot, improved precise shot chain. as well as the quicken spell like ability feat (and other spell like ability ones too).
Too many almost essential feats and not enough feats to go around.